The present invention relates generally to helical-scanning multi-channel type magnetic recording/reproducing apparatus such as video tape recorder (VTR), and more particularly to improvement of a rotary transformer used in such a magnetic recording/reproducing apparatus.
A helical-scanning type magnetic recording/reproducing apparatus includes a rotational drum and a fixed drum which are arranged to be in coaxially opposed relation to each other and has a rotary transformer between the rotational drum and the fixed drum for performing coupling between magnetic heads and a recording/reproducing circuit. The rotary transformer has a plurality of transformer coil assemblies for recording and reproduction each comprising a rotary side coil provided on the rotational drum and a fixed side coil provided on the fixed drum and further has an erasing coil assembly coupled to an erasing magnetic head. Generally, in order to prevent the magnetic leakage caused by signal currents between the transformer coil assemblies or between the transformer coil assemblies (windings) and the erasing coil assembly, which induces undesirable currents in the other unintended heads, a plurality of short rings are equipped between the coil assemblies, and the short rings as many as possible to meet requirements improves the function of preventing the leakage. However, the provision of a large number of the short rings causes congestion on the provision of the transformer coil assemblies and the erasing coil assembly because of limitation to the dimension, thereby resulting in deterioration of the performance of the rotary transformer such as transfer characteristics and frequency characteristics and in its number of turns influencing the quality of the recording and reproduction.